One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,6)(7,8)(10,11)(14,15)(17,18,20,22)(19,21,23,24)(25,26)(27,31)(28,36)(29,34)(30,33)(32,37)(35,40)(38,39)(1,3)(2,5)(4,7)(6,8)(9,10,13,11)(12,14,16,15)(17,19)(18,21)(20,23)(22,24)(25,27,29,30)(26,31,34,33)(28,35,37,38)(32,39,36,40)(2,6)(5,8)(9,11,13,10)(12,14,16,15)(19,23)(21,24)(25,28,29,37)(26,32,34,36)(27,35,30,38)(31,39,33,40)(3,7)(5,8)(9,12,13,16)(10,14,11,15)(26,33)(27,30)(31,34)(32,40)(35,38)(36,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.